Exp Clin Endocrinol Diabetes 2007; 115 - P02_138
DOI: 10.1055/s-2007-972545

Identification of occult metastases in medullary thyroid carcinoma via pentagastrin-stimulated intravenous calcitonin sampling followed by targeted surgery

C Sagert 1, H Willenberg 1, T Nguyen 1, S Schinner 1, M Cohnen 2, CF Eisenberger 3, WA Scherbaum 1, M Schott 1
  • 1University Hospital Düsseldorf, Department of Endocrinology, Diabetes and Rheumatology, Düsseldorf, Germany
  • 2University Hospital Düsseldorf, Department of Diagnostic Radiology, Düsseldorf, Germany
  • 3University Hospital Düsseldorf, Department of General and Visceral Surgery, Düsseldorf, Germany

Context: High calcitonin (CT) serum levels suggest metastatic spread in medullary thyroid carcinoma (MTC) after thyroidectomy. In limited disease stages, however, morphological investigations including ultrasound, MRI and [18F]FDG-PET may often fail to identify exact tumor sites.

Objective: The aim of the present study was to establish an improved strategy to identify small cervical tumors via pentagastrin stimulation with bilateral intravenous cervical CT sampling followed by high resolution ultrasound.

Methods: We examined 6 MTC patients of whom 5 patients already have had bilateral neck dissection. Five patients had sporadic MTC and one patient with MEN IIa. In each patient two catheters were placed in the lower parts of both internal jugular veins. Because of altered anatomy in patient 5, catheters were placed in the brachiocephalic veins. Thereafter, body weight-adapted (0.5 mcg/kg) pentagastrin stimulation was performed using peripheral blood sampling for control at baseline and 20, 40, 60 seconds after peripheral pentagastrin stimulation and thereafter every 30 seconds over 4 minutes. Peripheral blood CT assessment was performed in all patients for comparison.

Results: Retrospective analysis of all patients revealed a highly sensitive positive correlation between an early and unilateral calcitonin peak (20 to 40 seconds after administration of a body-weight-adapted pentagastrin dose) and site of cervical tumor affection. Postinterventional ultrasound examination of the affected regions of the neck revealed suspicious, small lymph nodes even less than 1cm in size, which were then surgically excised. On histology, small tumors could be identified in 4 patients. Postsurgical examination revealed a clear decline of serum calcitonin levels in 4 patients (from –41% to -100%). In 2 patients CT normalized to baseline levels (<10 pg/ml) and in another two patients CT rendered to near normal (14 and 17 pg/ml).

Conclusion: Pentagastrin stimulation-based intravenous catheter sampling may be beneficial to identify tumor-affected regions after thyroidectomy in MTC.